Electrical resistance element



Jan. 1, 1963 v. LUCIA ELECTRICAL RESISTANCE ELEMENT Filed Feb. 2. 1960 INVENTOR.

United lStates Patent @hice 3,071,748 Patented Jan. 1, 1963 3,071,748 ELECTRICAL RESISTANCE ELEMENT Louis V. Lucia, 16 Lincoln Ave., West Hartford, Conn. Filed Feb. 2, 1960, Ser. No. 6,257 3 Claims. (Cl. 2538-268) This invention relates to an electrical resistance element and more particularly Vto anelectrical heating element which is adapted to be inserted into an elongated tubular member.

An object of this invention is to provide such an element which can be completely assembled exteriorly of the tubular member and then readily inserted thereinto.

A further object is the provision of novel connection means contained entirely within said element for connecting the resistance wires thereof to electrical conductors leading therefrom to the exterior of the tubular member.r

A further object-is the provision of such an electrical heating element which is easy to assemble, durable, economical to produce and highly eicient in its operation.

Further objects and advantages of this application will be further understood from the following description and the accompanying drawing in which:

FIG. l is a side view, partly in section, of a radiator unit containing a heating element embodying my invention. f

FIG. 2 is an enlarged View, partly in central vertical section, illustrating the construction of said heating element.

FIG. 3 is an elevational end view of said heating element on line 3-3 of FIG. 2.

FIG. 4 is a side view, partly in section on line4-4 of FIG. 5, of a modified form of said heating element.

FIG. 5 is an end view thereof.

As illustrated in the drawing, my improved electrical heating element is particularly adapted for use in heat transfer units such as a radiator which may consist of a tubular member 5 having thereon a plurality of heat transfer tins 6.

The said heating element is constructed of a series of insulating tubes 7, of a suitable refractory material, which have a plurality of parallel holes 8 extending lengthwise therethrough.

In the form shown in FIG. 2, an electrical resistance, preferably in the form of a wire coil 9, is contained in a pair of said holes 8 of a series of said tubes 7 which are disposed end to end.y The two parallel portions of said coil are connected at the end of the heating element, preferably by a bend 10 in the coil which abuts the end of the respective tube 7 and anchors the said resistance coil against lengthwise movement within the holes 8.

'Ihe free ends 11-11 of the said resistance coil 9 are connected to lead conductors 12-12 which are preferably of stranded wire having a cover of asbestos and commonly known as heater wire. The connections between the coil 9 and said lead wires 12-12 is made by suitable connectors 13-13 which are preferably in the form of metallic sleeves; the ends of the coil and the lead wires being inserted into said sleeve from the opposite ends thereof which are crimped at 14 to securely bind the said ends of the wires together and provide tight electrical connections between the resistance coil and the lead wires 12-12.

The said lead wires are projected from the end of the tube 7 in which said connections are contained and are passed through an insulating bushing 15 of refractory material having an axial hole 16. 'Ihe said hole being of such a diameter that the leads 12-12 are bent, at 17-17, over the edges of the material between the holes 8 in which the coil is contained and enter said hole in Such a manner that the bends thus formed engage the edges of the holes 8 and anchor the connected ends of the resistance coil 9 against lengthwise movement withinthe holes 8.

The opposite end of the heating element is protected by a suitable insulating disc 18, which is also of refractory material, and the tube 5 is preferably crimped inwardly to provide a flange 19 which abuts the said disc 18 and retains it in position.

In the manufacture of said heating element, the resistance coil 8 is first doubled and then pulled through the holes 8 of the number of tubes 7 required for the length of the heating element desired. The leads 12-12 are then connected to the ends of the resistance coil in the manner above described and the connections are then allowed to be pulled back by the coil into the holes 8 of the end tube, or `said connections may be pulled into said end tube after they are made. The bushing V15 is then slipped over, the leads 12-12 and they are bent as at 17-17 whereby the said connections are retained in position within the respective tube and the resistance coil is anchored. By pulling on the leads to stretch the resistance coil 9 before forming the bends 17-17, the tension in said resistance coil can be utilized to pull the plurality of tubes 7 together end to end and thereby providing a heating element which is substantially ridged so that it can be easily handled.

The complete heating element may be installed in the member by first inserting the disc 18 into the open end of said member 5 and then inserting the complete heating element and pushing it and said disc until the element is fully contained within the tube. The said heating element is preferably secured within the member 5 by means of a securing member 2t), preferably in the form of a connector, that is attached to the end of the member 5, preferably by a clamping screw 21, and hasy a threaded projection 22 which can be inserted through an opening in a suitable terminal box 23 that is secured to the member 20 by a nut 24. The said member 20 is provided with a shoulder that abuts a shoulder 25 on said bushing 15 and retains the entire heating element against lengthwise movement within the member 5.

In the form illustrated' in FIG. 4, the heating element includes two resistance coils 26 and 27 which are connected in parallel and each is contained within a separate pair of the holes 8 in the tubes 7 and may be bent around the end of the inner tube in the same manner as above described for the coil 9 in FIG. 2. The ends 28-28 and 29-29 of each of said coil, respectively, are extended from the holes in the last tube 7 and connected together to a single lead wire 30 by means of a sleeve type connector 13 while the opposite ends of the coils 26 and 27 are also connected to another lead wire 30 in the same manner. After the said connections have been made, an additional tube 7-a, which may be crosssectionally identical to the tubes 7, is slipped over the leads 30-30 and the connectors 13-13 so that they will be contained within two holes 8 in opposite sides of the tube 7-a. The bushing 15 may then be slipped over the leads 30-30 and the entire heating element is ythen completed and may be inserted into the tube 5 in .disposed end to end and having therein a plurality of an electrical resistance coil contained in said holes, a pair Y of lead wires connected to the ends of said resistance coil and extending from an end of said series, the connections for said lead wires being contained within said holes, and a bushing of insulatingy material at the outer end of the said series, the said leads extending through an axial hole in said bushing and being bent into said hole whereby the bends of said leads abut the edges of the holes in the end tube of said series and secure the resistance coil against lengthwise movement within said tubes.

2. An electrical resistance element constructed of a series of identical insulating tubes disposed end to end and having therein a plurality of aligned parallel holes runningk lengthwise therethrough, said series including; an end tube at an end thereof, a plurality of resistance coils each having parallel portions separately contained in spaced pairs of said holes, the parallel portions at one side of each of said coils having lead portions extending into a common hole in said end tube Yand the parallel portions at the other side of each of said coils having lead portions extending into a separate common hole in said end tube, the Vsaid lead portions in each of saidcommon holes being connected together, an end bushing adjacent said end tube having an axial hole therethrough; and a pair of lead wires connected to all of the connected lead portions in each of said common holes and extending therefrom through said axial hole in said end bushing whereby said lead wires are bent and engage the edges of said common holes for anchoring said coils against longitudinal movement within said seriesv portions at the other side of each of said' coils having lead portions extending into a, separate common hole in said end tube, the said lead portions in each of said common holes being connected together, and lead wires connected to said lead portions in each of said common holes and extending outwardly from said end tube.

References Cited in the tile ofthis patent UNITED STATES PATENTS 1,238,124 Frickey Aug. 28,` 19.17 1,432,435 Abbot Oct. 17 1922 1,490,242 Thornton Apr. l5, 19,24 1,828,635 Abbot Oct. 20, 1931 1,905,232 Kercher et al. Apr.,25, 1 933 2,851,571 Pearce ,Sept. 9, -19,5 8 v2,878,355 VMcDonald Mar. 17, 1959 

1. AN ELECTRICAL RESISTANCE ELEMENT CONSTRUCTED OF A SERIES OF IDENTICAL INSULATING TUBES OF REFRACTORY MATERIAL DISPOSED END TO END AND HAVING THEREIN A PLURALITY OF ALIGNED PARALLEL HOLES RUNNING LENGTHWISE THERETHROUGH, AN ELECTRICAL RESISTANCE COIL CONTAINED IN SAID HOLES, A PAIR OF LEAD WIRES CONNECTED TO THE ENDS OF RESISTANCE COIL AND EXTENDING FROM AN END OF SAID SERIES, THE CONNECTIONS FOR SAID LEAD WIRES BEING CONTAINED WITHIN SAID HOLES, AND A BUSHING OF INSULATING MATERIAL AT THE OUTER END OF THE SAID SERIES, THE SAID LEADS EXTENDING THROUGH AN AXIAL HOLE IN SAID BUSHING AND BEING BENT INTO SAID HOLE WHEREBY THE BENDS OF SAID LEADS ABUT THE EDGES OF THE HOLES IN THE END TUBE OF SAID SERIES AND SECURE THE RESISTANCE COIL AGAINST LENGTHWISE MOVEMENT WITHIN SAID TUBES. 